The present invention relates to wheel slip prevention control, and, more particularly, to a system for controlling a vehicle to prevent the slippage of a driven wheel thereof occurring in response to the variations of the vehicle driving condition.
Various types of wheel slip or slipping prevention control systems have been developed with a view to preventing the slippage of driven wheels of a vehicle occurring when starting or accelerating to meet increasing demands for the vehicle's drivability.
One known technique involves controlling the output of the internal combustion engine of a vehicle when the slippage of a driven wheel thereof is detected by deriving the difference between the rotational speeds of the wheel driven by the engine and the non-driven wheel following the driven wheel.
Another approach to resolution of the slipping problem, such as is disclosed in Japanese Patent Provisional Publication No. 59-68538, is that the throttle opening of a carburetor is controlled on the basis of a slip ratio of a the driven wheel derived as a function of driven wheel speed and that of a non-driven wheel speed.
However, such prior art systems are arranged to merely vary the throttle opening of a throttle valve in stages in accordance with the detected slipping condition of a driven wheel, and therefore difficulty would be encountered to effectively and efficiently meet the requirements for eliminating the driven wheel's slippage problem. Thus, a further improvement would be required from the viewpoint of effectively preventing the wheel slippage and increasing the vehicle's drivability.